The site of Castelgrande has been fortified since at least the late 1st century BC and until the 13th century it was the only fortification in Bellinzona. During its history the castle has been known as the stronghold (before the 13th century), the Old Castle in the 14–15th centuries, Un Castle after 1506 and Saint Michael's Castle from 1818.
The Castelgrande hill includes a nearly vertical side on the north and a steep southern side, but is nearly flat and 150–200 meters in diameter. The natural shape of the hill has encouraged every man-made fortification to follow the same contours. While the Roman fort is not visible the Roman foundations were used by the High Middle Ages castle which followed. Of the High Middle Ages castle the only visible parts are a few pieces of wall that are still standing. Much of the visible castle dates from 1250–1500 with extensive renovations and some expansion in the last two centuries. Most of the area inside the castle walls is now flat, open space.
Records from the 11th to 15th centuries as well as archeological evidence indicate that the castle grounds were once full of buildings. However most of these were pulled down by the Dukes of Milan to free up interior space. The open space was divided into 3 large baileys which served to provide temporary housing for troops that could be stationed in Bellinzona. Under the Dukes of Milan the outer fortifications were extended and strengthened. The walls were raised, extended and towers were added. The western walls were totally rebuilt and connected to the city walls.
The walls that separate the three baileys all radiate from the 14th century Terre Nera, which is located in the center of the castle. To the east is a complex of buildings which were part of the old keep in the castle. In the center of the keep is the tallest tower of Castelgrande, the Torre Bianca or White Tower, which dates from the 13th century. Surrounding the Torre Bianca is the palace of the Bishop of Como (mentioned in the 12th century), which may contain masonry from an earlier 10th or 11th century structure. The nearby South Wing, which marks the southern boundary of the castle, was built in two stages during the 13th and 15th centuries on the foundations of an earlier building. To the west of the South Wing is a building that was built as an arsenal during the 19th century, and was fully renovated in the 20th century.
Archeological research has revealed that there were two chapels located in this bailey, though only the foundations have been discovered. In the western bailey the ruins of a church, possibly dedicated to the Madonna, can still be seen along the wall. The rest of the buildings that once occupied this bailey have all been destroyed. In the north bailey there were certainly buildings, though they have been destroyed. The sheer cliff face was not fortified with a wall until the 14th or 15th century.
The Castles of Bellinzona are a group of fortifications located around the town of Bellinzona, the capital of the Swiss canton of Ticino. Situated on the Alpine foothills, the group is composed of fortified walls and three castles named Castelgrande, Montebello and Sasso Corbaro. The Castles of Bellinzona with their defensive walls have been an UNESCO World Heritage Site since 2000.
The Broch of Gurness is an Iron Age broch village. Settlement here began sometime between 500 and 200 BC. At the centre of the settlement is a stone tower or broch, which once probably reached a height of around 10 metres. Its interior is divided into sections by upright slabs. The tower features two skins of drystone walls, with stone-floored galleries in between. These are accessed by steps. Stone ledges suggest that there was once an upper storey with a timber floor. The roof would have been thatched, surrounded by a wall walk linked by stairs to the ground floor. The broch features two hearths and a subterranean stone cistern with steps leading down into it. It is thought to have some religious significance, relating to an Iron Age cult of the underground.
The remains of the central tower are up to 3.6 metres high, and the stone walls are up to 4.1 metres thick. The tower was likely inhabited by the principal family or clan of the area but also served as a last resort for the village in case of an attack.
The broch continued to be inhabited while it began to collapse and the original structures were altered. The cistern was filled in and the interior was repartitioned. The ruin visible today reflects this secondary phase of the broch's use.
The site is surrounded by three ditches cut out of the rock with stone ramparts, encircling an area of around 45 metres diameter. The remains of numerous small stone dwellings with small yards and sheds can be found between the inner ditch and the tower. These were built after the tower, but were a part of the settlement's initial conception. A 'main street' connects the outer entrance to the broch. The settlement is the best-preserved of all broch villages.
Pieces of a Roman amphora dating to before 60 AD were found here, lending weight to the record that a 'King of Orkney' submitted to Emperor Claudius at Colchester in 43 AD.
At some point after 100 AD the broch was abandoned and the ditches filled in. It is thought that settlement at the broch continued into the 5th century AD, the period known as Pictish times. By that time the broch was not used anymore and some of its stones were reused to build smaller dwellings on top of the earlier buildings. Until about the 8th century, the site was just a single farmstead.
In the 9th century, a Norse woman was buried at the site in a stone-lined grave with two bronze brooches and a sickle and knife made from iron. Other finds suggest that Norse men were buried here too.